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Urine Odor Signals UTI in Infants

— Bad-smelling urine is a good predictor of urinary tract infection (UTI) in infants -- better than several other associated predictors, researchers found.

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Bad-smelling urine is a good predictor of urinary tract infection (UTI) in infants -- better than several other associated predictors, researchers found.

Though malodorous urine did not definitively rule in or out the diagnosis of UTI, foul-smelling pee remained a statistically significant predictor of UTI after adjusting for gender and presence of vesicoureteral reflux (OR 2.73, 95% CI 1.46 to 5.08), according to Marie Gauthier, MD, of the Sainte-Justine University Hospital Center in Montreal, Canada, and colleagues.

Action Points

  • Note that prior studies looking at the value of malodorous urine as a predictor of urinary tract infection in children have been contradictory.
  • Point out that this study indicates that parental report of malodorous urine increases the likelihood of UTI among young children with suspected UTI, but the association lacks specificity and cannot be used to rule in or out a UTI diagnosis.

Additionally, patients with malodorous urine who also presented with fever of unknown origin better predicted a UTI, the authors reported in the May issue of Pediatrics.

Previous studies assessing the value of malodorous urine in diagnosing UTIs in children have had contradictory results, the authors noted in their introduction.

In this study, the researchers measured presence or absence of foul-smelling urine against presence or absence of UTI, as well as other related UTI symptoms, in 331 patients age 1 to 36 months who presented at the authors' hospital emergency department.

Researchers gathered data through a parental questionnaire that asked about the infant's past medical history, symptoms shown within 48 hours of emergency department visit, and parental identification of malodorous urine (defined as urine that smelled stronger and/or more offensive). Other data, including information on why the urine culture was performed as well as culture results, were obtained through medical record review.

Of the 331 patients, 51 (15%) met the UTI diagnosis criteria. Foul-smelling urine was the risk factor most strongly associated with UTI, with 57% of those with a UTI also having reported foul-smelling urine (unadjusted OR 2.83, 95% CI 1.54 to 5.20).

However, 32% of patients without a UTI also were reported as having malodorous urine.

All patients with a UTI also had fever of unknown origin, as did 92% of those without a UTI.

Other risk factors for UTI included female sex (OR 2.82, 95% CI 1.41 to 5.61) and presence of vesicoureteral reflux (OR 2.39, 95% CI 1.04 to 5.53). Age and past history of UTI were not significant predictors of UTI.

Researchers noted that, although the association was strongest between urine odor and UTI, more than 40% of patients with a UTI did not have bad-smelling urine, and more than 30% of patients without a UTI did have bad-smelling urine.

"Although parental reporting of malodorous urine increased the probability of UTI, in particular in children with [fever without a symptom], it did not have a sufficiently high specificity or sensitivity to definitely rule in or rule out a UTI," Gauthier and colleagues wrote.

The authors also noted a number of limitations with their study, including no standardized definition of "malodorous urine," lack of direct observation of malodorous urine, lack of evaluation in patients without fever or only presenting foul-smelling urine, confounds in parental reporting, and low number of patients with a UTI.

Disclosures

The study was funded by the Fonds d'operation pour les projects de recherche clinique appliquee, CHU Sainte-Justine, Montreal.

The authors had no conflicts of interest to disclose.

Primary Source

Pediatrics

Gauthier M, et al "Association of malodorous urine with urinary tract infection in children aged 1 to 36 months" Pediatrics 2012; DOI: 10.1542/peds.2011-2856.